feat(session): record open live streams in the session store

Live stream ownership is only tracked in process memory, so no replica can tell
which pod holds a stream open once that pod is gone.

- persist a LiveStreamSession record when the live stream mappings change
- delete the record when the stream is closed
- keep closing the stream when the store is unreachable

tests/Jellyfin.Server.Implementations.Tests/SessionManager/SessionManagerTests.cs

@@ -11,6 +11,7 @@ using MediaBrowser.Controller.Drawing;
 using MediaBrowser.Controller.Dto;
 using MediaBrowser.Controller.Events;
 using MediaBrowser.Controller.Library;
+using MediaBrowser.Controller.MediaEncoding;
 using MediaBrowser.Controller.Net;
 using MediaBrowser.Controller.Session;
 using MediaBrowser.Model.Session;
@@ -41,7 +42,8 @@ public class SessionManagerTests
             Mock.Of<IServerApplicationHost>(),
             Mock.Of<IDeviceManager>(),
             Mock.Of<IMediaSourceManager>(),
-            Mock.Of<IHostApplicationLifetime>());
+            Mock.Of<IHostApplicationLifetime>(),
+            new NullTranscodeSessionStore());
 
         await Assert.ThrowsAsync(exceptionType, () => sessionManager.GetAuthorizationToken(
             new User("test", "default", "default"),
@@ -68,7 +70,8 @@ public class SessionManagerTests
             Mock.Of<IServerApplicationHost>(),
             Mock.Of<IDeviceManager>(),
             Mock.Of<IMediaSourceManager>(),
-            Mock.Of<IHostApplicationLifetime>());
+            Mock.Of<IHostApplicationLifetime>(),
+            new NullTranscodeSessionStore());
 
         await Assert.ThrowsAsync(exceptionType, () => sessionManager.AuthenticateNewSessionInternal(authenticationRequest, false));
     }
@@ -238,7 +241,8 @@ public class SessionManagerTests
             Mock.Of<IServerApplicationHost>(),
             Mock.Of<IDeviceManager>(),
             Mock.Of<IMediaSourceManager>(),
-            Mock.Of<IHostApplicationLifetime>());
+            Mock.Of<IHostApplicationLifetime>(),
+            new NullTranscodeSessionStore());
     }
 
     // All sessions are logged with the same client and device id on purpose, those values are taken